Holley 670cfm?
#1
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Car: 1984 Trans Am
Engine: Built chevy 350
Transmission: TCI Built 700r4
Axle/Gears: 3.73 posi 10 bolt
Holley 670cfm?
I just bought a Camaro that someone stuffed a late 80's Chevy truck 350tbi in. I do believe these TBI's flow 530 CFM...so I was looking at the Holley 670cfm but started to wonder about a 454tbi from an old Chevy truck, how much do they flow? Is Holley just making a 454tbi and selling it as a performance upgrade to a 350 motor?
Last edited by 4playta; 02-21-2010 at 04:21 PM.
#2
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Re: Holley 670cfm?
It would be very easy and cheap for you to port the larger stock TB unit, but keep in mind that the major limitation to air flow is in the TBI cylinder heads. Putting the money into the Holley unit wouldn't really pay off while using stock TBI heads.
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Car: 1984 Trans Am
Engine: Built chevy 350
Transmission: TCI Built 700r4
Axle/Gears: 3.73 posi 10 bolt
Re: Holley 670cfm?
I already planed on changing the heads and cam but then my tbi is a bottle neck and I dont want to switch to a carb. What I need to know is if the $750 Holley 670cfm unit is the same as the $75 454 tbi I can get at a junk yard.
#4
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Re: Holley 670cfm?
The only data I lack on this is my own personal measurement of the larger TBI bore, because I don't have one on hand right now.
The only other verification you could get is to find someone with the larger factory TBI and have them measure the bore diameter.
If it is 2", then it is the same as the Holley 670 CFM unit.
If you don't know anyone with one, I'd go to the junkyard with my slide caliper and grab one.
There is also this note about the injectors from RBob. He suggests using the earlier factory injectors, or the later Holley injector units.
Get either a BBC TBI unit or a Holley 670 CFM unit. Just do some research first on which one to get. The later BBC units used small injectors at high pressure. No room for growth.
The early Holley units used Chrysler injectors which are terrible. Be sure if you get a used Holley that the injector leads exit the injector from the side.
The early Holley units used Chrysler injectors which are terrible. Be sure if you get a used Holley that the injector leads exit the injector from the side.
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